bevy/examples/3d/lightmaps.rs
Patrick Walton dd14f3a477
Implement lightmaps. (#10231)
![Screenshot](https://i.imgur.com/A4KzWFq.png)

# Objective

Lightmaps, textures that store baked global illumination, have been a
mainstay of real-time graphics for decades. Bevy currently has no
support for them, so this pull request implements them.

## Solution

The new `Lightmap` component can be attached to any entity that contains
a `Handle<Mesh>` and a `StandardMaterial`. When present, it will be
applied in the PBR shader. Because multiple lightmaps are frequently
packed into atlases, each lightmap may have its own UV boundaries within
its texture. An `exposure` field is also provided, to control the
brightness of the lightmap.

Note that this PR doesn't provide any way to bake the lightmaps. That
can be done with [The Lightmapper] or another solution, such as Unity's
Bakery.

---

## Changelog

### Added
* A new component, `Lightmap`, is available, for baked global
illumination. If your mesh has a second UV channel (UV1), and you attach
this component to the entity with that mesh, Bevy will apply the texture
referenced in the lightmap.

[The Lightmapper]: https://github.com/Naxela/The_Lightmapper

---------

Co-authored-by: Carter Anderson <mcanders1@gmail.com>
2024-01-02 20:38:47 +00:00

61 lines
1.7 KiB
Rust

//! Rendering a scene with baked lightmaps.
use bevy::pbr::Lightmap;
use bevy::prelude::*;
fn main() {
App::new()
.add_plugins(DefaultPlugins)
.insert_resource(AmbientLight {
color: Color::WHITE,
brightness: 0.2,
})
.add_systems(Startup, setup)
.add_systems(Update, add_lightmaps_to_meshes)
.run();
}
fn setup(mut commands: Commands, asset_server: Res<AssetServer>) {
commands.spawn(SceneBundle {
scene: asset_server.load("models/CornellBox/CornellBox.glb#Scene0"),
..default()
});
commands.spawn(Camera3dBundle {
transform: Transform::from_xyz(-278.0, 273.0, 800.0),
..default()
});
}
fn add_lightmaps_to_meshes(
mut commands: Commands,
asset_server: Res<AssetServer>,
meshes: Query<(Entity, &Name), (With<Handle<Mesh>>, Without<Lightmap>)>,
) {
for (entity, name) in meshes.iter() {
if &**name == "large_box" {
commands.entity(entity).insert(Lightmap {
image: asset_server.load("lightmaps/CornellBox-Large.zstd.ktx2"),
..default()
});
continue;
}
if &**name == "small_box" {
commands.entity(entity).insert(Lightmap {
image: asset_server.load("lightmaps/CornellBox-Small.zstd.ktx2"),
..default()
});
continue;
}
if name.starts_with("cornell_box") {
commands.entity(entity).insert(Lightmap {
image: asset_server.load("lightmaps/CornellBox-Box.zstd.ktx2"),
..default()
});
continue;
}
}
}